Advanced Custom Fields (ACF)

Advanced Custom Fields, commonly known as ACF, is a WordPress plugin developed by Elliot Condon and now maintained by WP Engine. It adds a robust interface for attaching custom fields to any content type in WordPress — text fields, image fields, relationship fields, repeater rows, flexible content layouts, and more. ACF Pro, the paid version, adds features like the Repeater field, Flexible Content field, and Options Pages.

ACF became so common that it’s essentially a de facto standard. Most WordPress developers either use ACF or have worked around it extensively. Sites built with it tend to have content structured in ways that go well beyond what WordPress’s default post meta system was designed to handle.

What ACF Data Looks Like Under the Hood

ACF stores its data in WordPress’s wp_postmeta table, which uses a key-value structure. Complex field types like Repeaters and Flexible Content are serialized into that structure in ways that require ACF itself (or a deep understanding of its serialization format) to read correctly. This is one reason migrating ACF data can be more involved than moving basic post content — you can’t always just read the raw database values and know what you’re looking at.

ACF also uses a field key system (like field_5a3b2c1d) to link field values to their definitions. Without the field definitions, the data can be ambiguous.

Migrating ACF to Statamic

Statamic has its own field system built in through blueprints and fieldtypes. The field types available in Statamic cover most of what ACF provides — text, images, relationships, repeatable rows (via the Replicator or Grid fields), and flexible content layouts (via the Bard field or Replicator). The underlying architecture is different, and field values are stored as YAML in flat files rather than serialized PHP in a database, but the end result for content editors is comparable.

Migration involves three steps: defining equivalent blueprints in Statamic, extracting the ACF data from WordPress, and transforming it into the format Statamic expects. For simple field types, this is straightforward. For complex Repeater or Flexible Content groups, it requires more careful mapping.

ACF Options Pages — a popular way to store site-wide settings in WordPress — translate naturally to Statamic’s Globals, which serve the same purpose.

For more on what happens to your custom fields during migration, see What about my WordPress custom fields and ACF data?. The WordPress to Statamic Migration service includes full content architecture translation.